A photonic ADC for radar and EW applications based on modelocked laser

This paper presents a WDM architecture of a photonic analogue to digital converter (ADC) for direct RF sampling in radar and EW digital receiver, the architecture is based on the parallel operation of an array of state-of-the-art electronic ADCs while the photonic sampling is achieved using a mode locked laser (MLL). The parallelisation is implemented through a novel technique for the slicing of the optical spectrum and the time interleaving of the colored pulses. A high dynamic range by bandwidth product of the ADC can be obtained. The MLL overcomes the jitter limitation in conventional electronic quartz references in electronic ADCs and can be also fiber optic distributed as reference clock for the Radar Tx and Rx functions. The test realized on the prototype is reported demonstrating a 5 Gbps sampling rate ADC.